I dont think the game will come down to Peyton vs. Sherman at all.   They want that to be a story so badly... but it won't...
IMO, it'll be two things... The DEN ground game being able to just keep scooting the ball down the field, and SEA making 2-3 big mistakes that cost them the game.  Think about that game against SF...  Russell wilson fumbles the ball on the opening play.  Then with 2 minutes left, SF is in a position to win it.   If Cap wasn't such a dummy with the poor pass into double coverage, the 49er can win that game.  Does anyone think with 3 chances at the endzone from that close, Peyton throws that pass?